i recently purchased an 1986 buffalo and after repairing several chains, adjusters etc. finally got to put it thru its paces.what a machine!however after 25 - 30 minutes of operating the 20 hp kohler just shuts down and will not start until an hour or so.motor will then restart and run strong for about 20 min. and quit again! any clue to what is happening? possibly vapor locking? if so how do i prevent? do not want to hurt motor ... any suggestions would be greatly appreciated

tried that and even installed new cap, gas line and filter. still no luck. did find if i open back of truck it will run all day. as soon as i close the bed it overheats in 20-30 minutes. anyone else with suggestions?

Charlie, You might try changing the spark plug wires - the graphite seems to break down after a while. If that doesn't help, my next guess would be the coil. I have had a few different vehicles and machines that had bad coils.

I am assuming that you have already pulled all the shields off and blown out the cooling fins.

ok. now iam getting ticked. ducted intake to engine and installed exhaust fan near muffler,still seems to be vapor locking even though temp is only at 140 .i will try the spark plug wires next, but it appears that the fuel in the filter is being sucked dry and very little fuel enters especially at full throttle. Thanks for the suggestion Fred! i will let u know what happens.

not that im sugjesting you buy a new fule pump but could it be the fuel pump? anyway to check your pump? what dose kholer use for a fuel pump anyway? i know on vangard motors the cheep plastic micuni fuel pumps go bad in both argo's and maxes if oil gets into the vacume line, vacume line for fuel pump should be removed before adding oil or oil chainge, then replace when done, if kholer uses same pump it's something to look into,

fuel pump is brand new...kohler uses standard 3 psi diaphram pump .....called factory and they said i should drilln out jets in carb that it may be running too lean....plugs do not indicate such....definitely problem with fuel flow...runs great until gas is sucked from filter..new cap, new line , new pump,new filter,and i emptied and flushed tank out...carb rebuilt and valve job on motor.could the 1/4 in. fuel line be the problem?should i run a 3/8 in line instead and will that deliver more fuel to filter? thanks for all the suggestions! dont want to give up yet...but i am stumped...also would an electric fuel pump help?

a vacume gage as was used in the old days to test automotive engines would also test low psi like your pump, your new pump might not receve enoph of a puls to deliver tha 3 lb's of presher! with a low psi gage try to find out how much psi your fuel is under, might not be delivering enoph puls to draw any gas from tank! i have this problem myself on one engine of mine and i got low psi gage and low psi regulater from auto zone, need only the electric fuel pump to compleat my low psi fuel system, and then my attex will runn, defenatly upgrade your fuel line to larger stuff,

Also you may want to check the physical location of the fuel filter. The fuel going to the filter should be gravity fed by the fuel tank or if the filter is after the pump, make sure gravity will fill the filter. I would use a smaller size filter also. The pumps work much better when there is no air in the fuel supply lines or filters.

HEY CHARLIE GRIFFIN: as you mention "if i open back of truck it will run all day".it"s clear that the buffalo problem isn"t the engine itself!!!.is excesive heat build inside machinery room........the most important issue about the cooling air issue IS HOW TO TAKE OUT FROM MACHINERY ROOM THE HOT AIR.....therefore you should try to enrute the hot air from engine to outside of machinery room (SOME METALIC OR FIBERGLASS TAYLORED MADE DUCT WILL BE SOLUTION)....doing that the integrated cooling fan will keep machinery room cooler!!!!!! and that should be the end for overheating and malfuntion on your engine

thanks for all the help!! i was ready to get rid of this beast,but i think it is fixed.ran a duct system from vent to intake of motor and mounted a marine blower motor on exhaust side of motor which moves 280 cfm of hot air out of the compartment!so far it runs great!ran it for an hour or so and it never missed a beat!checked top speed on gps and easily hit 20-21 mph! never got it to run that fast before.this web site is awesome and so are you guys that helped.now my buffalo is awesome too!